1. Field of the Invention
The present invention relates to a stopper device in a welding robot X type gun.
2. Prior Art
A conventional stopper device in a welding robot X-type gun is illustrated in FIG. 4.
A lower arm 22 fixed to a pressure cylinder 21 and an upper arm 25 connected to the pressure cylinder 21 by way of a rod 23 are respectively pivotally mounted on a pivoting portion 27 disposed at a tip end of a cradle 26 attached to a robot, not shown.
Stopper bolts 29 and 30 are respectively attached to the upper and lower arms 25 and 22 and adjustably disposed in confronting relation relative to a stopper receiver 28 protruding from the cradle 26. When the rod 23 is drawn into the pressure cylinder 21, from the state as illustrated in FIG. 4, the tip end of the upper arm 25 moves upward so that the stopper bolt 29 of the arm 25 is brought into contact with the stopper receiver 28. When the rod 23 is further drawn into the pressure cylinder 21, the tip end of the lower arm 22 moves downward so that the stopper bolt 30 of the arm 22 is brought into contact with the stopper receiver 28 whereby both the upper and lower arms 25 and 22 are kept open where no welding operation is carried out.
However, the conventional stopper device has a problem that the amount of adjustment of the amount of movements of the upper and lower arms relative to the stopper receiver is limited since the stopper bolts are brought into contact with both surfaces of the stopper receiver while the stopper receiver disposed between the upper and lower arms moves unstably because of the weight of the welding gun from the state where the welding gun is kept open, i.e. non-welding state to the state where the pressure cylinder supplies fluid under pressure to the upper arm, i.e. welding state (hereinafter referred to as transient time).